Circuit breaker



Dec. l, 1942. w, M SCOTT, JR 2,303,959

CIRCUIT BREAKER Filed April 27, 1940 ATTORNEY.

BY @ma- Patented Dec. 1, 1942 CIRCUIT BREAKER.

William M. Scott, Jr., Bryn Mawr, Pa., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Application April 27, 1940, Serial No. 332,037

5 Claims.

This invention' relates to switch gear and circuit breakers, and more particularly to a panel type combination switch and circuit breaker adapted for use in branch circuits of various types and arranged to be mounted upon a panel board together with other similar devices for controlling a plurality of circuits.

This invention is particularly directed to the housing of the panel board circuit breaker and the arrangement of the housing to facilitate assembly and to provide integral support for the members of the circuit breaker.

In the operation of branch circuitsl it is frequently important to connect or disconnect individual circuits from the main line without interfering with the operation of other similar circuits, and to arrange for overload protection for individual circuits so that in the event of any fault in any particular branch, that particular circuit may automatically be disconnected without interfering in any way with the operation of other circuits or with the operation of the main circuit itself.

Thus, in the operation of a plurality of small motors for various purposes in a Shop, it isimportant that any fault occurring in the circuit to a particular motor should not affect the operation of other motors or the main line to the end that continuous operation should, as far as possible, be maintained.

Likewise, in the operation of multiple dwellings or apartment houses where a plurality ofA Accordingly, instead of providing for the creation of a simple airy-gap between the movable contact member and the stationary contact in the present on-oil switch circuit breaker combination, it is important to provide Ifor theinterposition of actual physical dielectric barriers between the two contacts when they separate. For this purpose, the movable contact is biased t0- ward contact closing position and is separated from the stationary contact by the movement of a barrier between them, one barrier being used for manual operation, another for automatic operation; the two barriers moving in the same plane and the manually interposable barrier being used to reset the automatically interposable f barrier in non-interposing position'when that is all connected to a single main line, it is im portant that any particular circuit to any particular apartment be readily connectible to and disconnectible from the main line and that any fault in any particular circuit should not disturb the operation of any of the other circuits.

Accordingly, the purpose and object of the present invention is to provide a simple combination on-off switch and circuit breaker which may be mounted upon a panel board and connected between the main bus and the individual branch circuits in order to provide suitable manual or automatic control for each of the individual circuits.

In order to provide for panel board mountin of this type and in order further to provide for simplicity in operation and assembly and to facilitate mounting upon the panel board, it is imp ortant that the particular combination switch and circuit breaker be compact and nevertheless so arranged as to obviate any internal faults or short circuits.

desired. 4

The circuits and apparatus may be designed to carry (a) a maximum current above and below which small variation may occur, (b) a heavy momentary inrush current 'as in thermal devices such as lamps where operating resistance increases after being switched on, (c) starting currents for motors, (d) short periods such as may occur in motors.

When these momentary increases occur, the length of time they last should be limited by the circuit breaker, preferably in accordance with the square of the current and directly in accordance with the time (PT). Whenever the current exceeds the normal maximum` value, then however, the circuit should be interrupted as quickly as possible.

The present circuit breaker will trip automatically under either of these conditions in response to either an instantaneous trip mechanism which will operate where resistance drops to substantially zero, or to a thermal trip mechanism operating in accordance with the aforementioned PT characteristic.

An important object of the lpresent invention is to so arrange the housing of the circuit breaker that all o-f the members thereof may be supported by integral formations of the housing and members integrated therewith.

Still another and extremely important object of the present invention is the arrangement of the housing of the combination switch and circuit breaker, and the various parts thereof in such manner as readily to facilitate assembly.

'l'hat is, the housing is so formed and each of the parts is so formed that the parts may readily successively be placed in the housing from one side, the assembly operation requiring merely a series of successive steps without any requirement for complicated tools or complicated supporting and holding means for combining and supporting the members during assembly.

A still further object of the present invention is to so arrange the housing and each of the parts that when the cover plate is secured to the housing at one side thereof, each of the parts is securely locked in operative position.

Many other objects and uses of the present invention will in part be apparent and in part pointed out in the 4following description and drawing, in which:

Figure 1 is a side view of the combination switch and circuit breaker with the cover plate removed and with the contacts and various members arranged in open circuit position.

Figure 2 is a cross-sectional view taken. on line 2-2 of Figure 1.

Figure 3 is a view corresponding to a portion of Figure 2, showing the contacts in closed circuit position.

Referring now to Figure 1, there is here shown a combination switch and circuit breaker which comprises a principal housing 20 arranged to carry, support and position each of the mem- -bers of the on-off switch and circuit breaker.

'The housing 20 has peripheral ledges 2|, 2l upon which a suitable cover plate 21a may be mounted and secured thereto by means of the rivets 22, 22.

The combination switch and circuit breaker comprises a manual operating handle 23 and circuit connecting means, separable contacts and automatic tripping means hereinafter more particularly described.

The combination switch and circuit breaker of Figure 1 is of a form and construction peculiarly adapting it for panel board operation for controlling a series of branch or subsidiary circuits fed from a main line or bus.

Figures 1 and 2 show the various parts of the switch and circuit breaker combination in the ordinary open circuit position produced when the manual operating handle 23 has been moved to open circuit position and the contacts have been separated without the intervention of any automatic elements.

As will readily be seen from Figures yl and 2 the combination switch and circuit breaker comprises a terminal or circuit connecting member 30 having any suitable means such as the threaded perforation 3l therein for connecting' the circuit breaker to one terminal of the circuit. The current is led to the connecting lug 30 (which is preferably connected to the load) from the integrally associated conductive bar 32 which is connected, through the projecting lug -33 of the bar 32, to the bi-metallic element 34.

The bi-metallic thermal element is at the bottom thereof connected to the flexible wire connection, preferably a copper braid 35 which is in turn conductively connected to the solenoid coil 31. The solenoid coil 31 is connected by means of the integral connecting bar 38 to the movable contact-carrying bar 39, the said contact-carrying bar being preferably an integral extension of the bar 3B,

Contact carrying bar 39 as will preferably be seen in Figure 2, carries the main movable contact block 40. The current enters the movable contact block 40 at the movable contact surface 4I (see Figure 3) when the combination switchcircuit breaker is closed from the stationary ccntact surface 42.

The stationary contact surface 42 is carried by the stationary contact supporting bar 43 (see Figures 2 and 3) which is in turn connected by the angular lead-in bar 44 (see Figure 1) to the opposite terminal or lead 45 into which the current may be led from the bus bar.

It will thus be seen that when the circuit breaker is so arranged that one terminal 30 thereof is connected through the load to one pole of the circuit and the opposite terminal 43 (ccnnected to the stationary contact) is connected to the opposite pole of the circuit, then the current path is through the two contact surfaces 4| and 42, and that any breaking of these contacts, that is, any separation thereof, will result in an opening of the circuit. Such separation of the contacts may be accomplished either manually, whenever it may be desired, or automatically in response to faults or ovexl current conditions occurring in the circuit which the present circuit breaker is designed to protect.

For the purpose of separating contact surfaces 4|, and 42, it may be sumcient merely to move the movable contact a sufiicient distance away from a stationary contact so that the air or gases between them furnishes .sufficient dielectric interposition to prevent effectively the passage of current therebetween.

Where, owing to the fact that for panel board mounting of these circuit breakers, the various dimensions thereof must be compressed as far as possible and the amount of travel permissible in the movable contacts is relatively limited, then in order to effectively break the contacts apart so that no current may flow therebetween, the present structure relies not on a suiilcient movement of the movable contact to accomplish this purpose, but principally on the interposition of a physical barrier of dielectric material which either effectively serves to lengthen any possible arcing path beyond the limits within which an arc may be maintained for the particular current and voltage rating of the circuit breaker or effectively serves to prevent any arcing path whatever.

Accordingly, the manually operated interposer 50 mounted on the manual operating lever 23 by means of the rivets 5|, 5| secured to the foot 52 may be utilized to separate the contacts and open the switch. The entire manual operating lever comprises a finger grasping portion which may be knurled to ensure a firm fit, a central pivoting portion 6I which carries the foot 52 and to which is connected the interposer 5U. The interposer 5U is preferably formed and pressed from suitable insulating dielectric material to a thickness facilitating interposition between the movable and stationary contact. The central portion 6I has a central opening 10 into which projects a knife edge 1I preferably integrally molded with the entire handle portion 23.

When the manual operating handle 23 is mounted upon the spindle 12 so that the knife 'edge 1I thereof registers with the angle 14 of the spindle and so that the perforation 10 of the central portion 6i of the manual operating member cooperates with the remainder of the spindle 12, then the manual operating handle 23 may readily be rotated about the spindle within definite limits or stops. That is, the manual operating handle may be rotated from the open circuit position shown in Figure 1 to a closed circuit position wherein the movable contact 4l may be pressed against, the stationary contact 42 as seen in Figure 3, in each case the side of the knife edge approaching one of the surfacu of the cut-out 13 of the spindle.

aaoasss W During the actual rotation, the principal bearing surface between the manual operating handle and the spindle is the knife edge 1| of the manual operating handle pressing into the angle 14 of the spindle. Thus even though the perforation 10 of the manual operating handle is slightly larger in diameter than the greatest diameter of the spindle, nevertheless the pressure of the knife edge 1| of the handle into the angle 14 of the spindle furnishes an eill'cient, playless bearing.

The spindle 12 by being preferably integrally molded with the side wall of the housing or by being integrated therewith in any suitable manner providing a positive positioning element for the rotating members and provides a simplified means upon which the rotating members may be assembled.

The finger grasping portion 60 of the manual operating lever 23 projects through the slot 00 in the upper surface of the housing where its movement from open circuit to closed circuit position is limited by the integrally formed shoulders 02 and 83.

The spring 90 is so arranged relative'to the center of rotation of the manual operating lever that it yieldingly biases the member 23 either in open or closed circuit position by reason of the fact that the spring passes upon the center for either position of the member 23 and thus yieldingly locks the manual operating lever in place.

The compression spring 90 is mounted on a slidable steel bar or link 9| which terminates at one end thereof in a bearing surface 32. The end 03 of the bar projects through an opening in a suitable bearing plate 95 and slides freely in said opening; the opposite end of the bar is -engaged in a notch 96 of the central portion 6| of theV manual operating arm 23. i

The spring 90 is thus maintained under compression between the bearing plate 05 and the flanges of the yoke end of the bar 92. Since the spring passes beyond center when the manual operating arm 23 is in the position shown in Figure 1, where the handle 60 is against the shoulder 82 and since the spring also passes beyond center when the handle |50v is moved against the shoulder 83 and the interposer 50 is thus moved from its position between the contacts, the action of the spring is to yieldingly maintain the manual operating arm 23 in whatever position it may be set, Whether in open circuit position (against the shoulder 82) or in closed circuit position (against the shoulder 83).

In order that (upon removal of the barrier 50 from the position shown in Figure l of the rotation thereof about the pivot 12 in a counterclockwise direction with respect to Figure l so that no barrier is present between the contacts 40 and 42), the movable contact should be forced into closed current conducting contact with the stationarycontact, a lever spring |00 is provided which tends to drive the movable contact surface 4| down upon the stationary contact surface 42.

Thelever spring |00 is mounted upon a surface 0| of the housing and secured thereto by a washer |02 and one of the rivets 22a which serves to secure the cover plate to the housing. In order to ensure that the leaf spring will be accurately positioned to exert proper contact pressure upon the movable contact, a lug |03 extends from the leaf spring and registers with a recess |04 of the housing which registry serves to prevent undue rotation of the leaf spring around the screw 22a.

'The leaf spring |00 preferably is formed of any suitable elastic metal preferably of spring steel and is so arranged and bent as to exert vpressure upon the contact-carrying arm 30 in such direction as to bias the contact block 40 and the movable contact surface 4| thereof into engagement with the stationary contact surface 42, the end ||0 of the leaf spring |00 is sheared in such manner as to provide a pressure transmitting surface thereon which presses down upon the contact bar and to provide guide flanges ||2 and H3, the edges of which engage the sides of the contact-carrying bar 30, and prevent the escape of the contact-carrying bar from the leaf spring and vice-versa.

In order to obviate any friction that might be induced by the movement of the barrier between the contacts, a wheel |20 made of suitable insulating material is loosely mounted upon a rivet |2| which is in turn mounted in the perforation |22 of the movable contact block 40.

The stationary contact surface 42 projects somewhat as will be seen in Figure 3, above the main portion of the stationary contact-carrying bar 43. In order to protect the Bakelite housing 20 from the eil'ects of any momentary arcing that may occur during the instant of breaking of the contacts, an insulating plate of any suitable material |30 is placed upon the inner side of the housing and over the stationary contact supporting members.

The insulating plate |30 has an opening |3| which registers with the stationary contact surface 42 and an opening |32 which registers with the wheel |20.

A small plate |38 of insulating material is placed beneath the opening |32 to protect the housing 20 at |35 from any stray arcs that might momentarily exist. The existence of the opening |32 as will be seen in Figure 3 permits the contacts 40 and 42 to come into close abutting relation without any interference from the wheel |20.

When the interposer 50 slides between the contacts, it will first strike the wheel |20, thus raising the contact bar sumciently to permit the interposer to pass between the contacts. The removal of the interposer from between the contacts is not inhibited by the surfaces of the contacts but the interposer slides beneath the wheel and when withdrawn from beneath the wheel |20 the contacts may be engaged as seen in Figure 3.

An automatically operable interposer |50 is provided in order automatically to separate the contacts either in response to a sudden large drop in resistance or in response to an overload of lesser intensity but continuing to such an extent as to cause overheating.

The automatic interposer also comprises a central pivoting portion |5| which is mountable upon the spindle 12 and a latch engaging arm |52, and is arranged for mounting upon the spindle 12 in exactly the same manner as is the interposer 50, it, however, engaging the enlarged portion |54 of the spindle.

Thus the automatically interposable member |50 is iirst placed upon the side portion |54 of the spindle and then the manually operated interposer is placed thereon. The automatic interposer |50 has the same type of knife edge bearing as the interposer 50'in order to limit the rotation thereof.

A compression spring |10 controls the movement of the automatic interposer |50 and is mounted on a lead 1| which has a yoke which bears against a notch of the automatic interposer |50 in the same manner as has previously been described for the manual interposer 50 and the opposite end |14 is arranged to slide in the perforation |15 of the plate 35 in the same manner as is the link oi the spring 30.

The compression spring |10 is so arranged that it is always exerting a force tending to move the automatic interposer |50 into position between the contacts.

The interposer |50 is restrained from counterclockwise movement in response to the action of compression spring |10 by the latch engaging arm |52 thereof. The latch engaging arm |52 carries secured thereto by rivets or any other suitable fastening means, a steel bearing plate |80 which engages the latch |8| of the trigger |82. Upon movement of the trigger |82 in such a direction as to release the engagement between the metal bearing |80 and the latch |8| there is no further restraint upon the rotation of the barrier |50 and since the action of the compression spring |10 is such as to immediately initiate counterclockwise movement thereof with respect to Figure 1, then immediately upon such disengagement. the compression spring |10 will force the interposer |50 into position where it extends between the movable and stationary contacts.

The open circuit position of the barrier |50 is denitely ilxed by the abutment thereof against the edge of the handle shutter .'50A which thus halts continued rotation of the interposer |50 in response to the action of the spring |10,

By proper arrangement and spacing of the shutters (that is the closed circuit non-interposing position of the shutter 50 and the open circuit interposing position of shutter |50) it is possible to ensure that in the tripped position of the circuit breaker, the interposer |50 will be positioned directly between the movable and stationary contacts.

The abutment of the edges of the shutter in the tripped position forms a complete continuous seal between the contacts cutting ofi any possible effective arc path.

When by the operation of the manual operating lever 23, the barrier 50 is moved to closed circuit position, that is, to a position where it no longer extends between the movable contact and the stationary contact, no impediment of any kind exists to the automatic interposition of the interposer |50 between these contacts in response to a release of the latch engaging portion thereof |50 by the trigger |82.

Normally when no fault conditions exists upon a line, the trigger |82 is so arranged that the latch portion |8| thereof engages the bearing plate |80 of the interposer |50. For the purpose of retaining the interposer in the desired noninterposing position, the trigger |82 is spring biased by means of springs 200 (Figures 1 and 2) into latching position.

The trigger is mounted upon a spindle 2|0 preferably integrally formed from and secured to the wall of the housing and preferably having a notch therein within which a pointed projection of the latch may register to obtain a bearing of the type previously described in connection with interposers.

Any fault condition existing upon the line must be manifested in some mechanical way which may be utilized to cause a rotation of the trigger in such a direction as to release the latch engaging portion |52 of the interposer from the latch lll of the trigger. Accordingly, arms 220 and 22| are provided on the trigger to cooperate with elements which respond mechanically to variations in the amount of current.

Trigger release arm 220 is so arranged as to cooperate with the member 245 of the solenoid assembly 230. As has been above noted, the solenoid is in the current path through the movable and stationary contacts. Thus, with respect to Figure l, the current enters at the connecting lug or terminal 45, passes through the contact blocks and the member 33 and 38 into the coils 31 of the solenoid and thence through the wire braid 35, the thermal element 34 and the lug 33 and bar 32 into the opposite terminal 30.

The solenoid coil 31 is composed of several turns of conducting material which, in the preferred embodiment of the present invention, is square copper of substantial cross-section. The large cross-sectional area minimizes the resistance which is injected into the circuit and also increases the actual physical strength of the coil, thus making it possible to use an integral extension 38-39 of the solenoid coil itself as the leadn artid physical support for the movable contact loc It will be noted that the contact engaging spring |00 forces the contact member 40 toward the molded wall of the housing. The point of engagement of this spring with the bar 33 is between the contact and the coil. The spring thus produces reactions at each end of the bar 88-38; one, producing contact engaging pressure when the the interposers are retracted; the other maintaining the solenoid assembly in its socket.

To obviate the necessity for insulation on the solenoid, the coil preferably is wound with a reasonably large air space between the turns. The solenoid coil 31 is mounted on an insulating sleeve 23| which prevents any current leakage between the successive turns of the coil and at the same time serves to insulate the coil from other members of the mechanism.

The insulating sleeve 23| may be secured within the housing in any suitable manner. Thus one end thereof may at 232 be supported in a depression of the bottom wall of the housing and the opposite end thereof may be supported in a. U-shaped member 233 preferably integrally molded from a wall of the housing.

A suitable steel core may be mounted within the sleeve 23| and may have a flange which registers with the depression in the bottom wall of the housing. Any suitable spring maybe utilized within the sleeve to maintain the solenoid armature 240 in raised although slidable position Within the spring; the said spring being callbrated to permit the drawing of the armature 240 within the coils in response only to an overload sufliciently excessive to cause damage and should resist the tendency of the armature to move within the coils upon the occurrence ofoverloads which are not greatly excessive but are merely sufficient to cause the generation of heat. A rectangular trigger arm engaging member 245 is secured either by welding or by any other suitable means to the top of the armature. Preferably, the trigger arm engaging member 245 is squared-ofi and preferably the interior wall 245 is close to the plate 245 of the armature.

While the squaring-off of the plate 245 does not interfere with the rise or fall of the armature, it prevents undue rotation of the armature to ensure that the trigger arm engaging portion asoaosc thereof will always extend in such a direction as.

t engage the trigger and to ensure that it will not rotate out of engagement with the trigger. Means for preventing eddy currents may be provided in any suitable manner.

When an overload occurs for any reason causing an excessive current to pass through the coil 31 of the solenoid, then the armature 24|! is at- `tracted into the coil of the solenoid, the plate 245 engages the trigger arm 220, presses the arm downwardly, causes a rotation of the trigger about the spindle 2|0 in a direction opposite to that in which the trigger was originally biased by the trigger spring 200, causes a movement of vthe latch portion |8| thereof out of engagement with the bearing |80 of the latch engaging arm |52 ofthe interposer |50 and thus removes any restraint upon the rotation of the interposer |50, thereby permitting the compression spring |10 to drive the interposer from closed circuit position to a position wherethe interposer |50 extends between the movable and stationary contacts.

Thus whenever the manual interposer 50 is CFI ' trigger under predetermined excessive load conmoved counterclockwise with respect to Figure 1 from position between the contacts to the closed circuit position, then a free path is provided for the movement of the automatic interposer |50 to interposng position should an overload occur.

The automatic interposer |50 in its movement into position between the contacts obviously env gages the wheel in order to raise the mov- When the interposer moves between the contacts, since the circuit is then opened, any restraining force preventing resetting is removed. Upon rotation in a clockwise direction of the member in the manual operating arm 23, the automatic interposer |50 is reset in closed circuit position and subsequently upon counterclockwise movement of the manual interposer 50,

the contacts are permitted to meet as shown in Figure 3.

If, during such opening movement of the interposer 50, over current conditions still exist on the line, then the tripping action may again occur. It is thus absolutely impossible to hold the circuit closed when overcurrent conditions exist on the line and to this extent at least the present invention is a trip free circuit breaker.

It may be necessary or desirable to effect a similar tripping operation of the interposer |50 when an overload which is not greatly excessive but is nevertheless continuous occurs.

In order to accomplish this purpose, I provide a thermal bi-metallic element 34 which is responsive to heating effects which may occur in this circuit. 'I'he thermal bl-metallic element 34 is so arranged that the lower end thereof will be rotated clockwise under the inuence of heat. The current path from the connecting lug 45 through the contacts and to the connecting lug 30 is through the thermal element 84. Thus the current is led from connecting lug 45 through the bar 44 to the contact surfaces 42 and 4|, the contact supporting arm 39 and 38, the solenoid coil 31, the wire braid 35 to the thermal element;

from the thermal element, the current flows into ditions which are not greatly in excess of the desired current condition but which nevertheless result in the generation of excessive heat.

Upon bending of the thermal element 34 in response to such heating conditions in the circuit, the end thereof will be swung over into mechanical contact with the trigger arm 22| and will cause a rotation of the trigger |82 about the spindle 2 0, such rotation` releasing the latch portion |8| thereof from the metallic bearing |80 of the latch engaging arm |52 of the automatically interposable interposer 50.

This permits a tripping operation to occur and permits the compression spring |10 to force the automatically operated interposer |50 into the open circuit position.

The automatically operated interposer may then -be reset in the manner above described by the operationl of the manual operating lever 23, but the trigger |82 will not be rotated to latching position by its spring 200 until the heating conditions which resulted in a curling of the thermal element 34 have been removed.

The circuit breaker may be calibrated for various types of overload conditions by any suitable adjustment of the solenoid or its armature or by adjusting the screw 210 of the thermal element. Since the finger grasping portion may remain in the apparent closed circuit position against the shoulder 83 even though the automatic interposer |50 has been moved between the contacts, a visual ndicator300 may be provided carrying a flag 30| and having an opening 302 which permits it to be mounted on a spindle 12. A spring 308 tends normally to rotate the indicator 300 so that the flag 30| may be moved into the slot. A linger 305 however projects beneath the arm |52 of the automatic interposer and prevents the spring 308 from driving the flag upwardly into the slot.

Upon the raising of the arm by release of the latch plate |80, |80, the spring 308 may rotate the indicator 300 and drive the flag 30| into the slot thus giving a clear indication of the fact that the automatic interposer has been tripped, even though the linger grasping portion 60 should remain in apparent closed circuit position.

In order to prevent any possibility during the opening of the contacts of any arcing over between the movable contact block" 40 and the bar 44, insulating barriers 320 and 32| are provided mounted in notch 322 of the ledge or boss 323 in the bottom wall of the housing and in notches 324 and 325 of an end Wall of the housing, the said notches being integral with the housing.

In order further to protect the members against arcing, an upper shield 340 is provided (see Figure 2) having openings therein to permit the engagement of the contacts and the passage of the wheel therethrough. This protective shield may be formed or stamped to shape, the shape being, of course, determined by the contour of the housing and obviously this shield 340 is spaced from the bottom shield |36 by a distance suiiicient to permit the free passage of the insulating interposers between them.

From the foregoing description it will be seen that each of the members of the circuit breaker is supported within the housing in such a manner that they may readily be assembled in connection therewith. The housing itself is so formed and constructed as to provide supporting elements of various types, most of which having hereinbefore been described. Thus, for instance, the bar 32 which is an extension of the connecting lug 30 is securely mounted within the housing assembly by the screw 660 which passes through a lug 36| of the bar 32 and into an integrally molded rectangular support 363 of the housing. The bar 32 is also securely positioned within the housing by being mounted between the rectangular abutment 363 and the angular portion 364 of the housing.

Each of the interposers and the manual operating lever rotates about a single spindle which is integrally molded from or secured to one wall of the housing.

The member Il which carries the lug 45 is also securely mounted within the housing, as is seen in Figure 1, by being mounted in a recess or channel 366 thereof. The various portions of the housing cooperate with other elements to provide stops for certain of the movements and to provide mountings and securement in the manner hereinbefore described. When the cover plate is secured in place by the rivets 22, then each of the members is securely xed in its operative position. Thus, the final securement of all of the members is obtained after most of the members have merely been slipped into place by the attachment of the cover element 2i and the passing of the rivets 22 through the elements and the housing.

The lead connecting lug 30 is protected by the curved extension 36|! of the housing and may be enclosed between the cover plate and this extension. The lead 45 may, if desired, extend from the opposite side or it may, where necessary, be protected in a similar manner. A

The present circuit breaker is comprised of a magnetic trip and a thermal time delay element and may be incorporated in the usual form of power and light panel to handle branch circuits. The members as has been noted, are readily mounted in any suitable support upon the panel and require no more space than a fused switch, and, taking into consideration the expense of replacement of fuses and the expense of operation of the fused switch, they are better than an adequate substitute therefor.

They are designed to be mounted in a panel with a number of units side by side with the line terminal of each circuit breaker screwed directly to the common bus, this screw also serving to hold one end of the unit mechanically, the opposite end of the circuit breaker being mechanically supported in any suitable manner. In this manner, therefore, any individual units may be removed and replaced without disturbing adjoining units.

As has been above noted, the circuit breaker of the present invention is trip free in that it will open even though the handle is held in closed position and the switch cannot be held against overload or short circuit. The only way in which the circuit breaker may be reset after the interposer has been tripped is by moving the manually interposable interposer between contacts and thus maintaining the contacts in open circuit position. Should the vcircuit protected by the circuit breaker still be under overload conditions, then permitting the manually interposable interposer to be moved away from between the contacts will again cause the actuation of the thermal and/or solenoid elements to cause the automatically interposable interposer to move between the contacts and thus maintain the separation therebetween.

In the foregoing description while all of the operated elements have been set forth, it is particularly to be noted that each of these elements is mounted upon or supported by integral portions of the housing itself. Thus, the interposer ismounted upon a spindle which is integral with or integrated with the housing. 'I'he latch is likevwise mounted upon a spindle which is either integral with or integrated with the housing. The solenoid coil is mounted upon bearings which are integral with the housing and held within those bearings by a spring. The stationary contact is part of a lead-in bar which is mounted in recesses and channels within the housing.

The opposite terminal 30 and the connecting bar 32 is positioned by integral formations of the housing and secured to the housing. The spring which biases the movable contact and the various plates for preventing arcing over and for other purposes are each mounted in integrally formed portions of the housing.

All of the members, as has been specifically pointed out, may be place'd within the housing by successive steps from one side of the housing and then the securement of the cover plate 2Ia secures all of these members in place.

o described.

My specific invention is directed to the formation of the housing so that it will cooperate with each of the parts of the circuit breaker and support and position each of such parts.

Various modifications and changes in the different parts will now be obvious to those skilled in the art. Accordingly, it is desired to be bound not by the specic disclosures herein but only by the appended claims.

This application is filed simultaneously with the application of Frank J'. Pokorny, Serial No. 331,984 for Circuit breaker, the application of Herbert C. Graves, Jr., Serial No. 331,982 for Circuit breaker, and the application of Otto Jensen, Serial No. 331,967 for Circuit breaker. In this application, I have claimed those inventions and portions of the structure devised by me.

I claim:

1. A panelboard circuit breaker comprising switch members including separable contact means andmanual and automatic current responsive means for controlling said contact means, a housing therefor adapted to be mounted upon a plane support in contiguous side by side relation with other such housings, said housing comprising a box-like structure of rectangular shape havingl an open side, depressions in said housing communicating with the open side thereof, and cooperating with and positioning said switch members, a rectangular opening in one edge of said housing and a manually operable member extending therethrough and adapted by pivotal movement to actuate said separable contact means to open and closed circuit positions,

a slot in one end of said housing, a first rigid conducting terminal member extending therethrough, a perforation in said terminal on the outside of said housing for cooperation with screw means to connect said circuit breaker to an external circuit, the end of said terminal member inside of said housing being electrically associated with said separable contact means; a second conducting terminal member having one end electrically associated with said separable contact means and extending through a positioning slot in the end wall of said housing opposite to that traversed by said first terminal and means on the outside of said housing for connecting said second terminal to an external circuit, said housing having a plurality of channels lying in planes at substantial angles to each other for positioning each terminal the walls of the channels being substantially contiguous over said switch members, a rectangular opening in their entire extent with surfaces of said terminals, a cover for the open side of said housing for maintaining said switch members therein and securing means for said cover.

2. A panelboard circuit breaker comprising switch members including separable contact means and manual and automatic current responsive means for controlling said contact means, a housing therefor adapted to be mounted upon a plane support in contiguous side byside relation with other such housings, said housing comprising a box-like structure of rectangular shape having an open side, depressions in said housing ycommunicating with the open side thereof, and cooperating with and positioning said switch members, a rectangular opening in one edge of said housing and a manually operable member extending therethrough and adapted by pivotal movement to actuate said separable contact means to open and closed circuit positions, a slot in one end of said housing, a rst rigid conducting terminal member extending therethrough, a perforation in said terminal on the outside of said housing for cooperation with screw means to connect said circuit breaker to an external circuit, the end of said terminal member inside of said housing being electrically associated with said separable contact means; a second conducting terminal member having one end electrically associated with said separable contact means and extending through a positioning slot in the end wall of said housing opposite to that traversed by said iirst terminal and means on the outside of said housing for connecting said second terminal to an external circuit, said housing having a plurality of channels lying in planes at substantial angles to each other for positioning each terminal the walls of the channels being substantially contiguous over their entire extent with surfaces of said terminals, each terminal comprising a flat strip of metal bent to cooperate with the sides of the channels for positioning the same therein, a cover for the open side of said housing for maintaining said switch members therein and securing means for said cover.

3. A panelboard circuit breaker comprising' switch members including separable contact means and manual and automatic current reone edge of said housing and a manually operable member extending therethrough and adapted by pivotal movement to actuate said separable contact means to open and closed circuit positions, a slet in one end of said housing, a iirst rigid conducting terminal member extending therethrough, a perforationin said terminal on the outside of said housing for cooperation with screw means to rconnect said circuit breaker to an external circuit, the end of said'terminal member inside of said housing being electrically associated with said separable contact means; a second conducting terminal member having one end electrically associated with saidseparable contact means and extending through a positioning slot in the end wall of said housing opposite to that traversed by said ilrst terminal andmeans on the outside of said housing for connecting said second terminal to an external circuit, said housing having a plurality of channels lying in planes at substantial angles to each other for positioning each terminal the wall of the channels being substantially contiguous over their entire extent with surfaces of said terminals, each terminal comprising a fiat strip of metal bent to cooperate with the sides of the channels for positioning the same therein, a cover for the open side of the housing, said iirst terminal being positioned solely by the walls of the channels and the cover; said cover maintaining the switch members within the housing and securing means for the cover.

4. A panelboard circuit breaker comprising switch members including separable contact means and manual and automatic current responsive means for controlling said contact means, a housing therefor adapted to be mounted upon a plane support in contiguous side by side relation with other such housings, said housing comprising a box-like structure of rectangular shape having an open side, depressions in said housing communicating with the open side thereof, and cooperating with and positioning said switch members, a rectangular opening in one edge of said housing and a manually operable memberl extending therethrough and adapted by pivotal movement to actuate said separable contact means to open and closed circuit positions, a slot in one end of said housing, a first rigid conducting terminal member extending therethrough, a perforation in said first terminal on the outside of said housing for cooperation with screw means to connect said circuit f breaker to an external circuit, the end of said rst terminal member inside of said housing being electrically associated with said separable contact means; a second conducting terminal having one .end electrically associated withA said separable contact means and positioned by al positioning slot in the end wall of said housing opposite to that traversed by said first terminal, said housing having a plurality of channels lying in planes at substantial angles to each other for positioning said rst terminal; the walls of the channels being substantially contiguous over their entire extent with the surface of said first terminal, a cover for the open side of said housing for maintaining 'said switch members therein and .securing means for said cover.

5. 'A panelboard circuit breaker comprising switch members including separable contact means and manual and automatic current responsive means for controlling said contact means, a housing therefor adapted to be mounted upon a plane support in contiguous side by side relation with other such housings, said housing comprising a box-like structure of rectangular shape having an open side, depressions in said housing communicating with the open side thereof, and cooperating with and positioning said switch members, a rectangular opening in an external circuit, the end of said nrst terminal member inside of said housing being electrically associated with said separable contact means; a second conducting terminal having one end electrically associated with said separable contact means and extending beyond the end wall of said housing opposite to that traversed by said iirst terminal; said housing having a plurality of channels lying in planes at substantial angles to each other for positioning said iirst terminal; the walls oi the channels being substantiaily contiguous over their entire extent with the surface oi' said rst terminal, a cover for the open side of said housing for maintaining said switch members therein and securing means i for said cover.

WILLIAM M. SCOTT, Jl. 

